1. Field of the Invention
The present invention relates to a relay device, a network system, and a method of controlling the relay device, and more particularly to a relay device that mediates communication between an information processing apparatus that displays an operation screen provided from an external apparatus, and performs processing corresponding to an operation on the operation screen and the external apparatus, and a method of controlling the relay device.
2. Description of the Related Art
Conventionally, an image processing apparatus is generally known which accommodates component parts having respective functions of a scanner, a printer, a facsimile machine, a network transmission device, and so forth, within a single casing. Further, it is also popular to use a Web browser in a console section of such an image processing apparatus. Japanese Patent Laid-Open Publication No. 2006-203869 discloses a form of use of the above-mentioned functions on an operation screen displayed by a Web browser.
According to Japanese Patent Laid-Open Publication No. 2006-203869, the Web browser installed in an image forming apparatus displays an operation screen concerning image processing functions based on screen information (screen data) received from an external apparatus on a network. Then, upon receipt of a user's operation using the operation screen, the web browser transmits information on the operation received from the user to the external apparatus. Thereafter, the image forming apparatus receives a Web service request based on the user's operation from the external apparatus. The image forming apparatus executes the scan function or the print function of the image forming apparatus in response to the Web service request.
However, a firewall sometimes exists between an information processing apparatus provided with a Web browser and an external apparatus on a network. In general, the firewall allows connection from the inside to the outside, but does not allow connection from the outside to the inside. For this reason, the above-mentioned method of the Japanese Patent Laid-Open Publication No. 2006-203869 is sometimes incapable of receiving a Web service request from an external apparatus.
Further, when an MFP (multi-function peripheral) exists in an environment in which addresses are used while translating between public and private addresses by a network address translator (NAT), it sometimes occurs that an MFP requesting a Web service cannot be identified by an external apparatus on the network.